Generally, long-wheelbase trailers provide support for a vertical load between two or more axles of a trailer, which may be towed, connected, or attached to a vehicle. Practical applications for long-wheelbase trailers may include an ability to tow larger masses utilizing smaller vehicles without compromising one or more stability characteristics. Stability characteristics or the dynamics between a vehicle and a long-wheelbase trailer towed by the vehicle are among the factors to consider when designing or operating a vehicle connected to, attached to, or towing a trailer (e.g., a vehicle-trailer system). A yaw stability of a vehicle towing a long-wheel based trailer (e.g., trailer) is generally considerably lower than a yaw stability of the vehicle by itself. For example, a vehicle coupled with a trailer generally demonstrates or exhibits a reduced damping ratio of yaw dynamics, which may progressively worsen as the velocity of the vehicle-trailer system increases.
A vehicle with a trailer in tow may have different or additional modes of instability than merely a vehicle without a trailer attached. For example, jackknifing between the vehicle and the trailer may occur, such as when the trailer swings about a hitch connecting the vehicle and the trailer. Explained another way, when there is a large amount of relative yaw motion between the vehicle and the trailer, jackknifing may occur. As another example, instability may occur as a result of oscillation, such as lateral oscillation, or as a result of snaking, which is oscillation of the trailer when high velocities are reached. In yet another example, instability may occur as a result of a phase lag or a phase difference between characteristics of the vehicle and the trailer, such as a phase lag between the vehicle motion and the trailer motion caused by a distance separating the two (e.g., a separation distance). Yet another cause of instability may include rearward amplification (RWA) between a vehicle and a trailer. Rearward amplification is an increased lateral acceleration at a center of gravity (CG) of a trailer to that a center of gravity of a vehicle or a lead vehicle attached to the trailer operating one or more maneuvers or dynamic maneuvers.
Regardless, instability or unstable motion, such as excessive yaw motion or undesired yaw motion associated with a vehicle or a trailer is generally not desired. Further, instability or unstable motion may be exacerbated for a vehicle when a trailer is attached to the vehicle and a vehicle-trailer system is formed. When a trailer is attached or coupled to a vehicle, a lower yaw stability margin or unstable dynamics may result from attachment of the trailer.